Fluorescent lamp starter



May 14, 1946. c. HODGKlNs 2,400,353

FLUORESCENT LAMP STARTER Original Filed June 24, 1942 INVENTOR c'. H. HODG/(l/VS ATTORNEY Patented May 14, 1946 r 2,400,353 FLUORESCENT LAMP STARTER Charles H. Hodgkins, Fairfield, Conn., asslgnor to The Bryant Electric Company, Bridgeport, Conn., a corporation of Connecticut Original application J unc 24, 1942, Serial No. 448,190, now Patent No. 2,344,774, dated March 21, 1944. Divided and this application May 1, 1943, Serial No. 185,289

6 Claims.

The present invention relates to gaseous discharge lamps and particularly to the starting and operating i such lamps of the fluorescent type from the usual source of electrical energy of the customary domestic potential, and constitutes a division of my prior Patent No. 2,344,?7i, granted March 21, 1944, and assigned to the same assignce as the present invention.

it is customary with lamps of this type to con nect the filamentary electrodes in series with an inductance element across the domestic source of supply and a relay device, such as shown in Patent 2,200,443, issued May it, 1946, to C. Bench, is employed to fiISl'; connect the rilamem tary electrodes in a series heating circuit to raise the temperature thereof to electron emissivity, after which the relay operates to interrupt the series heating circuit and causes a high voltage surge from the series connected inductance, which thus initiates a discharge between the preheated electrodes.

The dimculty with such circuit arrangement resides in the tact that if the discharge lamp be comes defective and the discharge accordingly fails to start for any reason, the relay continues to operate indefinitely, thus not only shortening its useful life but since it repeatedly completes and interrupts the series heating circuit for the filamentary lamp electrodes, the latter will con tinuousiy glow and constitute a source of annoyance to the user because oil the low efiiciency of the radiation thus produced which is a waste of electrical energy.

It is accordingly an object of the present invention to provide a starting and operating arrangement for a gaseous discharge lamp wherein a relay unit is employed to initiate a discharge in the lamp while consuming no energy during operation of the latter, and which relay unit operates to prevent glowing of the lamp electrodes by locking-out the lamp in the event a discharge is not initiated therein after several operations of the relay.

Another object of the present invention is the provision of a relay unit for starting and operating a gaseous discharge lamp which can be readily inserted in the socket for the lamp and. is operable to initiate a, discharge in the latter while consuming no energy once such discharge is started, but in the event the lamp becomes defective, the relay operates to "lock-out the lamp.

Still further objects of the present invention will become obvious to those skilled in the art by reference to the accompanying drawing wherein:

Fig. 1 is a sectional view in elevation of the relay unit of the present invention and showing the relative arrangement of the various parts;

Fig. 21s a view similar to that of Fig. l but taken at 99 to the latter;

Fig. 3 is a sectional view taken on the line Ill-11! of Fig. 1;

i is a diagrammatic illustration of the starting and operatin circuit oi the present invention and employing the relay unit as shown in the preceding figures;

Fig. 5 is a sectional view taken on the line VV of Fig. 6 and showing a modification. which the relay unit of the present invention may take, and

Fig. 6 is a top plan view of the modification as shown in Fig. 5.

Referring" now to the drawing in detail, the relay unit l shown in 1 comprises a casing of a plastic material or light metal permanently closed at one end and having its other end closed by an insulating cap provided with a pair of socket terminals i and ii and held in place as by bent lugs protruding from the casing t.

Disposed within this casing is a glow switch it] of the type shown in Patent 2,228,210, issued January '7, 194:1, to it. Hays, Jn, comprising a vitreous envelope provided with an ionizable medium at a suitable pressure and having a pair of electrodes i2 and it, one of which it is a bimetallic element, as shown more clearly in Fig. a.

'A radio frequency-suppressing condenser M is also housed within the casing and is connected directly to the socket terminals "l and t by conductors it and it. in addition a thermal relay is supported within the casing t which comprises a base of insulating material ii. A pair of metallic eyelets or the like it and it pass through this base ill and. a high ohmic resistance heater to has its ends connected to these eyelets it and it which positions the heater Eli a little above the insulated base it.

Partially surrounding this heater 2t is a heatresponsive element in the form of a substantially U-shaped bimetallic member 22 having its shorter rear leg secured to a conducting strip 23 disposed on the back of the base ii and extending horizontally part way thereacross, and from which a conductor 24 extends to one of the electrodes it of the glow switch it. The free depending end of the bimetallic element 22 is provided with a contact 2t normally engaging a metallic contact member 26. This latter contact 26 is arranged in heat transfer relationship with a series resistance heater 21 to which one end of the latter is connected, while the remaining end of the heater 2! is connected to the eyelet l8 and hence to the socket terminal 5 as well as to one side or the condenser II.

By reference now more particularly to Fig.4, the circuit arrangement utilizing therelay unit above described is schematically illustrated. As therein shown a discharge lamp 28 which may be of the well known fluorescent type is provided with a pair or filamentary electrodes 28 and 20. One end of the electrode 25 is connected through an inductance or choke coil 32 to one side of a domestic source of supply Li of the customary domestic potential of 115-330 volts. In a similar manner, one end of the electrode 30 is connected through a switch 35 to the other side of the supply source L2 with the remaining ends of the electrodes 29 and Ill being connected together to thus form a series heating circuit therefor, by the relay unit 4.

Upon closure of the switch 53, the full voltage of the supply source Ll-L2 will be impressed across the electrodes 12 and ll of the glow switch I. by a circuit which extends from one side of the supply source Ll through electrode 29 to socket terminal I, thence to bimetallic electrode l2, and from electrode 13 through bimetallic member 22, contacts 25 and 25, series resistance ferred to contact 25 and thence by conduction to the bimetallic member 22, to cause the free end thereof to deflect away from the base 11 and interrupt thenormal engagement of the contacts 25 and 25. This deflection of the bimetallic member 22 thus disconnects the series heater 21 from the circuit and at the same time removes the former short-circuit from the high ohmic resistance heater 20, thus placing the latter in series with the glow switch ll.

Although the high ohmic resistance heater 25 will thus be in the circuit, its characteristics are such that the current is limited to a value where a very low current glow discharge results in the glow switch l which is insumcient to heat the bimetallic electrode i2 enough to cause it to deflect into engagement with the stationary electrode 13. At the same time the high ohmic resistance heater 25 supplies sufiicient heat to maintain the contacts 25 and 25 in an open circuit 7 position which thus "locks-out" the defective heater 21, to socket terminal and thence through lamp electrode 20 and switch 33 back to the other side of the supply source L2. The condenser I4 is in electrical parallel with the glow switch as well as the thermal relay, while the high ohmic resistance is short-circuited by the normally closed contacts and 25.

Thi supply voltage is sumcientiy high to cause a glow discharge to take place in the glow switch III which rapidly heats the bimetallic electrode i2, causing it to deflect into engagement with the stationary electrode II, thereby completing a series heating circuit for the lamp electrodes 28 and I5. By the time these electrodes have reached electron-emitting temperature, the bimetallic electrode l2 of the glow switch ill will have cooled and will return to its normal position. At the instant of separation of the electrodes [2 and It, a high voltage surge will be impressed across the preheated filamentary lamp electrodes 28 and 30; thus initiating a discharge in the lamp. If for any reason the discharge is not initiated upon the first completion of the cyclic operation of the glow relay III, the latter will continue repetitious operation due to application of the supply voltage thereto until the lamp 28 is in operation. Moreover, during operation of the lamp the relay unit 4 consumes no energy. since the voltage drop across the lamp is below that necessary to again reestablish a glow discharge in the glow switch Ill.

The operation of the circuit as shown in Fig. 4 and thus far described differs in no way from that as shown and described in the above noted Patent 2,228,210, to R. F. Hays, Jr. However, as above noted, such an arrangement possesses the disadvantage that should the lamp fail to start due to deactivation of its filamentary electrodes or similar cause, the glow relay will continue to go through its cyclic operation, causing repeated glow of the lamp electrodes with material shortening of the useful life of the glow switch.

In the circuit arrangement of the present invention such disadvantage is eliminated by the provision of the relay unit as above described. For example, if the lamp 2! fails to start after a few cyclic operations of the glow switch ill, the series resistance heater 21 continues to build up heat with each operation of the glow switch [5 until suillcient heat is developed which is translamp, preventing unnecessary and futile repetitious operation of the glow switch it, thereby preserving its useful life and at the same time eliminating glowing of the lamp electrodes 29 and 30. Upon replacement of the defective lamp, the relay unit returns to its normal position ready to operate in the manner above described to start the new lamp.

In Figs. 5 and 6 a modification of the relay unit 4 is shown which differs from that previously described merely in positioning of the various parts (with the exception of the condenser I4) in a single vitreous envelope. By reference to these latter figures it will be noted that a vitreous envelope 411, closed at one end 42, is provided with a partition 43, also of the same vitreous material as the envelope 40, which is hermetically sealed to the interior of the envelope. As viewed from Fig. 5, two chambers are thus formed, the lower chamber 44 being evacuated and then filled with a suitable gas through an exhaust stem 45, while the upper chamber 46 may be open to the atmosphere.

A U-shaped bimetallic electrode 41 is supported upon a leading-in and supporting conductor 45 which extends to the socket terminal such as 1 shown in Fig. l and corresponds to the bimetallic electrode I2. A stationary electrode 48 is likewise disposed in the hermetically sealed chamber 44 and extends through the partition 43 where it is secured to a short connecting strap 50 with an upstanding projection 52 which is connected to a U-shaped bimetallic member 53 corresponding to the member 22 previously described relative to the preceding modification. A high ohmic resistance heater 54 likewise has one of its ends connected to the strap 50, while its other end is connected to a similar strap 55 extending to a leading-in condutcor 58 which connects to the socket terminal such as 8 shown in Fig. 1.

Again the free end of the bimetallic member 5! is provided with a contact 51 normally engaging a contact 58 embedded in the partition 45 and in electrical heat transfer relation to a series resistance heater 58 to which one end of the heater is electrically connected as in the previously described modification. Also, the remaining end of the series resistance heater is connected by a conductor 60 to the stra 55 which thus completely connects all of the various elements of the modiilcation of Figs. 5 and 6 in the identical relationship as shown in the circuit arrangement oi Fig. 4, so that either the modification of Figs. 1-3 orthat of Figs. 5-6 can be readily inserted in a socket,

since the latter construction is likewise housed within the casing I together with the condenser ll.

It thus becomes obvious to those skilled in the art that a simple yet efficient circuit arrangement is provided by the present invention wherein a relay unit is employed for the starting and operating of a discharge lamp, particularly of the fluorescent type, which relay consumes no energy during operation ofthe lamp. Moreover, when the lamp becomes defective and will accordingly not start after a predetermined period of time following initial operation of the relay unit, the latter automatically operates to lock-out the defective lamp and effectively disconnect the same from the source, thereby preserving the useful life of the relay unit and at the same time eliminating the former annoyance of continued glowing of the electrodes of the defective lamp.

Although several embodiments of the present invention have been shown and described, it is to be understood that still further modifications of the present invention may be made without departing from the spirit and scope of the appended claims.

I claim:

1. A relay unit adapted to start and operate a discharge lamp comprising a casing, an hermetically sealed chamber within said 'casing provided with an ionizable medium and a pair of electrodes therein one of which is a heat-responsive element for sustaining a discharge therebetween until said heat-responsive element is heated by the discharge and deflects into engagement with the other electrode to short-circuit said discharge, and a second chamber within said casing provided with actuating means in series with the electrodes within said hermetically sealed chamber and having a pair of normally closed contacts for completing the circuit to said electrodes and to said actuating means, and said contacts being operable by said actuating means to open the series connection of said electrodes and actuating means after the lapse of a period of time upon continued repetitious operation of said electrodes within said hermetically sealed chamher, and a current limiting'meanswithin said second mentioned chamber and connected. in series with said electrodes by opening of said contacts and operable to maintain the latter in an open position and to limit the discharge current between said electrodes to a value insuflicient to cause the discharge to raise the temperature of said heat-responsive element to the point where it deflects into engagement with the other electrode, in the event said discharge lamp becomes defective.

2. A relay unit adapted to start and operate a discharge lamp comprising a casing, an hermetically sealed chamber within said casing provided with an ionizable medium and .a pair of electrodes therein one of which is a heat-responsive electrode for sustaining a discharge therebetween until said heat-responsive electrode is heated by the discharge and deflects into engagement with the other electrode to short-circuit said discharge, and a second chamber within said casing provided with a bimetallic element and a resistance heater in series with the electrodes within said hermetically sealed chamber and having a pair of contacts normally closed by said bimetallic element for completing the circuit to said electrodes and to said resistance heater, and said contacts being operable by said bimetallic element to open the series connection .of said electrode and said resistance heater after the lapse of a period of time upon continued repetitious operation of said electrodes within said hermetically sealed chamber, and a current limiting means within said second mentioned chamber and connected in series with said electrodes by opening of said contacts and operable to heat said bimetallic element and maintain said contacts in an open position and said means being operable to limit the discharge current between said electrodes to raise the temperature of said heat-responslve electrode to the point where it deflects into engagement with the other electrode, in th event said discharge lamp becomes defective.

3. A relay unit adapted to start and operate a discharge lamp comprising an envelope provided with a partition therein to form two chambers one of which is hermetically sealed and provided with an ionizable medium and a pair of electrodes one of which is a bimetallic electrode for sustaining a discharge therebetween until said bimetallic electrode is heated by the discharge and deflects into engagement with the other electrode to short-circuit said discharge, and a bimetallic element and a resistance heater in the other chamber in series with the electrodes within said hermetically sealed chamber and having a pair of contacts normally closed by said bimetallic element for completing the circuit to said electrodes and to said resistance heater, and said contacts being operable by said bimetallic element to open the series connection of said electrodes and said resistance heater after the lapse of a period of time upon continued repetitious operation of said electrodes within said hermetically sealed chamber, and a current limiting resistance in said other chamber and connected in series with said electrodes by opening of said contacts and operable to heat said bimetallic element and maintain said contacts in an open position, and said current limiting resistance being operable to limit the discharge current between said electrodes to a value insufficient to cause the discharge to raise the temperature of said bimetallic electrode to the point where it deflects into engagement with the other electrode, in the event said discharge lamp becomes defective.

4. 1A relay unit adapted to start and operate a discharge lamp comprising a casing, an hermetically sealed chamber within said casing provided with an ionizable medium and a pair of electrodes therein, one of which is a heat-responsive element for sustaining a discharge therebetween until said heat-responsive element is heated by the discharge and deflects into engagement with the other electrode to short-circuit said discharge, and a second chamber within said casing provided with actuating means in series with the electrodes within said hermetically sealed chamber and having a pair of normall closed contacts for completing the circuit to said electrodes and to said actuating means, and said contacts being operable by said actuating means to open the seriesconnection of said electrodes and activating means after the lapse of a period of time upon continued repetitious operation of said electrodes within said hermetically sealed chamber, and a resistance heater unit within said Second mentloned chamber and operable by opening of said contacts to maintain the latter in an open position in the event said discharge lamp becomes defective and until the latter is replaced.

5. A relay unit adapted to start and operate a discharge lampcomprising a casing, an hermetically sealed chamber within said casing provided with an ionizable medium and a pair of electrodes therein. one of which is a heat responsive electrode for sustaining a discharge therebetween until said heat responsive electrode is heated by the discharge and deflects into engagement with the other electrode to short-circuit said discharge, and a second chamber within said casing, an electri heater within said second chamber, a heat responsive element in heat transfer relation with said electric heater, a pair of contacts normally closed by said heat responsive element for completing a series circuit to said electrodes within said hermetically sealed chamber and to said electric heater, said electric heater being operable only after the lapse of a period of time upon continued repetitious operation of said electrodes within said hermetically sealed chamber to transfer suflicient heat to said heat responsive element to cause the latter to open said contacts and interrupt the series connection of said electrodes and said electric heater, and a resistance heater 23 said contacts in an open position in the event said 25 discharge lamp becomes defective and until the latter is replaced.

6. A relay unit adapted to start and operate a discharge lamp comprising a casing, a glow switch within said casing provided with an envelope having an ionizable medium and a pair of electrodes therein, one of which is a heat responsive element for sustaining a discharge therebetween until said heat responsive element is heated by the discharge and deflects into engagement with the other electrode to short circuit said discharge, a bl-metallic member in said casing, a low resistance electric heater in heat transfer relation with said bi-metallic member, a pair of contacts normally closed by said bi-metallic member for completing a series circuit to the electrodes of said glow switch and to said low resistance heater, said low resistance heater being operable only after the lapse of a period of time upon continued repetitious operation of said glow switch to transfer sufficient heat to said bi-metallic member to cause the latter to open said contacts and interrupt the series connection of the electrodes of said glow switch and said low resistance heater, and a high resistance electric heater in heat transfer relation to said bi-metallic member and shortcircuited by the normal closure of said contacts and operable upon the opening of the latter to continuously heat said bi-metallic member in the event said discharge lamp becomes defective and until the latter is replaced.

CHARLES H. HODGKINS.

Disclaimex v 2,400,353.-0faarles H. H edgkins, Fairfield, Conn. FLUORESCENT LAMP STARTER. Patent dated May 14, 1946. Disclaimer filed June 14, 1951, by the assignee, The Brywnt Electric Company. Hereby enters this disclaimer to claims 4, 5, and 6 of said patent.

[O'fiicial Gazette July 10, 19-51.]

Disclaimers v 2,400,353.-0/wrles H. Body/kins, Fairfield, Conn. FLfiQREsCENT LAMP by the assignee, The Bryant Eleatm'oflompany.

STARTER. Patent dated May 14:, 1946. 1 Disclaimer filed J mm 14, 1951,

Hereby enters this disclaimer to claims 4, 5, and 6 of said'patent.

[Ofiioial Gazette July 10, 1951.] 

